The present invention relates to optical apparatus using variable optical-characteristic optical devices such as a variable configuration mirror and also relates to imaging apparatus using such optical apparatus.
Generally, the size and performance of an equipment as a whole are likely to depend on its optical system in the types of imaging equipment such as a film camera, digital camera, and video camera, and display equipment and also in a microscope, electronic endoscope, etc. The reduction in size and power consumption is thus always demanded of the optical system not only of the imaging equipment and display equipment but also of each of the above described equipment to improve the performance, especially downsizing and power saving. Such a demand is most intense in the field of digital cameras and camera units of mobile phone, i.e., digital imaging equipment.
While the optical system of some of the above described equipment has been provided with an autofocus function and/or zoom function, these functions are achieved by driving a lens by motor.
As a means for achieving downsizing and power saving of the optical system in which a lens is driven by motor, a variable configuration mirror has disclosed for example in Japanese patent application laid-open Hei-11-317894. Such a variable configuration mirror is constituted by a thin film for forming a reflecting surface and an electrode disposed in a manner facing the thin film. A voltage is applied between the thin film and the electrode to change a curved shape of the thin film of the reflecting surface by electrostatic force so that its focal length can be adjusted. The variable configuration mirror is smaller in size and lower in power consumption as compared to the conventional motor-driven optical system and is characterized in that it does not cause a motor drive sound or noise in its transmission system.
Further, Japanese patent application laid-open No.2000-267010 discloses variable optical-characteristic optical devices such as a variable focal lens and variable prism in addition to the above described variable configuration mirror, which are of special construction unlike those conventional optical component parts made of glass or plastic and have optical characteristics that are variable by an electrical control.